Novel pigment grinding vehicles

ABSTRACT

It has been found that quaternary onium (e.g., ammonium, sulfonium, and phosphonium) salt group-containing epoxy resins are particularly useful as grinding media in preparing stable pigment disperions useful in water-dispersible coating systems, for example, electrodepositable compositions. The resins are prepared by reacting a material selected from the group consisting of amine salts, phosphine-acid mixtures, and sulfide-acid mixtures with a 1,2-epoxy group containing material wherein a ratio of at least about 0.4 eqivalents of quaternary onium groups are produced per equivalent of epoxy group initially present. Preferably, the system contains at least a small amount of polyoxyalkylene glycol.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of Application Ser. No.281,098, filed on Aug. 16, 1972, now abandoned.

STATE OF THE ART

In the formulation of paint compositions and especiallyelectrodepositable paint compositions, an important factor is theintroduction of pigments into the coating composition. Pigments aretypically ground in a dispersing agent and then the resultant pigmentpaste is incorporated into the coating composition to give the coatingcomposition proper color, or opacity, and application or filmproperties.

The time required for grinding and dispersing pigments poses a problemin some instances. Further, electrodepositable compositions have beenfrequently found wherein the resin which ultimately makes up themajority of the vehicle present in the composition is not suitable as agrinding medium, since the pigment paste formed does not have stableproperties and, upon storage for any length of time, produces acomposition which cannot be readily dispersed and/or which adverselyaffects the properties of the electrodepositable composition ultimatelyformed.

DESCRIPTION OF THE INVENTION

It has now been found that where an epoxy group containing quaternaryonium (e.g., ammonium, sulfonium or phosphonium) base salt groupsolubilized resin is employed as a grinding media in preparing stablepigment dispersions useful in water-dispersible coating systems thatsubstantially improved stability is obtained where the ratio of finalquaternary onium groups to initial epoxy groups is at least 0.4 to 1.Preferably, the grinding system contains at least a small amount ofpolyoxyalkylene polyol.

The cationic resins which can be utilized in preparing the compositionsof this invention are characterized as ungelled, water-dispersibleresins containing quaternary onium (preferably ammonium) salt groups,and preferably containing epoxy groups. It has been found that thepresently-preferred resins are based on polypoxide resins, wherein theresultant resin contains at least one free epoxy group per averagemolecule and wherein the resin contains oxyalkylene groups and/or thesalts forming the quaternary onium salt of an acid having a dissociationconstant greater than 1 × 10⁻ ⁵.

Generally, the quaternary onium salt may be the salt of boric acidand/or an acid having a dissociation constant greater than boric acid,including organic and inorganic acids. Upon solubilization, at least aportion of the salt is preferably a salt of an acid having adissociation constant greater than about 1 × 10⁻ ⁵. Preferably the acidis an organic carboxylic acid. The presently preferred acid is lacticacid.

The presently preferred resins contain at least one epoxy group andpreferably contain about 0.05 percent to about 16 percent by weight ofnitrogen and at least about 1 percent of said nitrogen, preferably about20 percent, more preferably about 50 percent and, most preferably,substantially all of the nitrogen being in the form of chemically-boundquaternary ammonium base salt groups; preferably the remainder of saidnitrogen being in the form of amino nitrogen.

The epoxy group-containing organic material can be any monomeric orpolymeric compound or a mixture of compounds having a 1,2-epoxy group.It is preferred that the epoxy-containing material have a 1,2-epoxyequivalency greater than 1.0, that is, in which the average number of1,2-epoxy groups per molecule is greater than one. It is preferred thatthe epoxy compound be resinous or a polyepoxide, i.e., it contains morethan one epoxy group per molecule. The polyepoxide can be any of thewell-known epoxides. Examples of these polyepoxides have, for example,been described in U.S. Pat. Nos. 2,467,171; 2,615,007; 2,716,123;3,030,336; 3,053,885 and 3,075,999. A useful class of polyepoxides arethe polyglycidyl ethers of polyphenols, such as Bisphenol A. These maybe produced, for example, by etherification of a polyphenol withepichlorohydrin or dichlorohydrin in the presence of an alkali. Thephenolic compound may be bis(4-hydroxyphenyl)2,2,-propane,4,4'-dihydroxybenzophenone, bis(4-hydroxyphenyl)1,1-ethane,bis(4-hydroxyphenyl)1,1-isobutane;bis(4-hydroxytertiarybutylphenyl)2,2-propane,bis(2-hydroxynaphthyl)methane, 1,5-hydroxynaphthalene, or the like.Another quite useful class of polyepoxides are produced similarly fromnovolak resins or similar polyphenol resins.

Also suitable are the similar polyglycidyl ethers of polyhydric alcoholswhich may be derived from such polyhydric alcohols as ethylene glycol,diethylene glycol, triethylene glycol, 1,2-propylene glycol,1,4-butylene glycol, 1,5-pentanediol, 1,2,6-hexanetriol, glycerol,bis(4-hydroxycyclohexyl)2,2-propane, and the like.

There can also be used polyglycidyl esters of polycarboxylic acids whichare produced by the reaction of epichlorohydrin or a similar epoxycompound with an aliphatic or aromatic polycarboxylic acid, such asoxalic acid, succinic acid, glutaric acid, terephthalic acid,2,6-naphthylene dicarboxylic acid, dimerized linolenic acid, and thelike. Examples are diglycidyl adipate and diglycidyl phthalate.

Also useful are polyepoxides derived from the epoxidation of anolefinically unsaturated alicyclic compound. Included are diepoxidescomprising, in part, one or more monoepoxides. These polyepoxides arenon-phenolic and are obtained by epoxidation of alicyclic olefins, forexample, by oxygen and selected metal catalysts, by perbenzoic acid, byacetaldehyde monoperacetate or by peracetic acid. Among suchpolyepoxides are the epoxy alicyclic ethers and esters which are wellknown in the art.

Another class of polyepoxides are those containing oxyalkylene groups inthe epoxy molecule. Such oxyalkylene groups are typically groups of thegeneral formula: ##EQU1## where R is hydrogen or alkyl, preferably loweralkyl (e.g., having 1 to 6 carbon atoms) and where, in most instances, mis 1 to 4 and nis 2 to 50. Such groups can be pendant to the mainmolecular chain of the polyepoxide or part of the main chain itself. Theproportion of oxyalkylene groups in the polyepoxide depends upon manyfactors, including the chain length of the oxyalkylene group, the natureof the epoxy and the degree of water solubility desired. Usually theepoxy contains at least about 1 percent by weight or more, andpreferably 5 percent or more of oxyalkylene groups.

Some polyepoxides containing oxyalkylene groups are produced by reactingsome of the epoxy groups of a polyepoxide, such as the epoxy resinsmentioned above, with a monohydric alcohol containing oxyalkylenegroups. Such monohydric alcohols are conveniently produced byoxyalkylating an alcohol, such as methanol, ethanol, or other alkanol,with an alkylene oxide. Ethylene oxide, 1,2-propylene oxide and1,2-butylene oxide are especially useful alkylene oxides. Othermonohydric alcohols can be, for example, the commercially availablematerials known as Cellosolves and Carbitols, which are monoalkyl ethersof polyalkylene glycols. The reaction of the monohydric alcohol and thepolyepoxide is generally carried out in the presence of a catalyst.Formic acid, dimethylethanolamine, diethylethanolamine,N,N-dimethylbenzylamine and, in some cases, stannous chloride are usefulfor this purpose.

Similar polyepoxides containing oxyalkylene groups can be produced byoxyalkylating the epoxy resin by other means, such as by direct reactionwith an alkylene oxide.

The polyepoxide employed to produce the foregoing epoxies containingoxyalkylene groups contain a sufficient number of epoxy groups so thatthe average number of residual epoxy groups per molecule remaining inthe product after the oxyalkylation is greater than 1.0. Whereoxyalkylene groups are present, the epoxy resin preferably contains fromabout 1.0 to about 90 percent or more by weight of oxyalkylene groups.

Other epoxy-containing compounds and resins include nitrogeneousdiepoxides such as disclosed in U.S. Pat. No. 3,365,471; epoxy resinsfrom 1,1-methylene bis(5-substituted hydantoin), U.S. Pat. No.3,391,097; bisimide containing diepoxides, U.S. Pat. No. 3,450,711;epoxylated aminomethyldiphenyl oxides, U.S. Pat. No. 3,312,664;heterocyclic N,N'-diglycidyl compounds, U.S. Pat. No. 3,503,979; aminoepoxy phosphonates, British Pat. No. 1,172,916; 1,3,5-triglycidylisocyanurates, as well as other epoxy-containing materials known in theart.

Another class of resins which may be employed are acrylic polymerscontaining epoxy groups. Preferably these acrylic polymers are polymersformed by copolymerizing an unsaturated epoxy-containing monomer, suchas, for example, glycidyl acrylate or methacrylate.

Any polymerizable monomeric compound containing at least one CH₂ =Cgroup, preferably in terminal position, may be polymerized with theunsaturated glycidyl compounds. Examples of such monomers include:

1. Monoolefinic and diolefinic hydrocarbons, that is, monomerscontaining only atoms of hydrogen and carbon, such as styrene,alpha-methyl styrene, alpha-ethyl styrene, isobutylene (2-methylpropene-1), 2-methylbutene-1,2-methyl-pentene-1,2,3-dimethyl-butene-1,2,3-dimethyl-pentene-1,2,4-dimethyl-pentene-1,2,3,3-trimethyl-butene-1,2-methyl-heptene-1,2,3-dimethyl-hexene-1,2,4-dimethyl-hexene-1,2,5-dimethyl-hexene-1,2-methyl-3-ethyl-pentene-1,2,3,3-trimethyl-pentene-1,2,3,4-trimethyl-pentene-1,2-methyl-octene-1,2,6-dimethyl-heptene-1,2,6-dimethyl-octene-1,2,3-dimethyldecene-1,2-methyl-nonadecene-1,ethylene, propylene, butylene, amylene, hexylene, butadiene-1,3,isoprene, and the like;

2. Halogenated monoolefinic and diolefinic hydrocarbons, that ismonomers containing carbon, hydrogen, and one or more halogen atoms,such as alpha-chlorostyrene, alpha-bromostyrene, 2,5-dichlorostyrene,2,5-dibromostyrene, 3,4-dichlorostyrene, ortho-, meta- andpara-fluorostyrenes, 2,6-dichlorostyrene, 2,6-difluorostyrene,3-fluoro-4-chlorostyrene, 3-chloro-4-fluorostyrene,2,4,5-trichlorostyrene, dichloromonofluorostyrenes, 2-chloropropene,2-chlorobutene, 2-chloropentene, 2-chlorohexene, 2chloroheptent,2-bromobutene, 2-bromoheptene, 2-fluorohexene, 2-fluorobutene,2-iodopropene, 2-iodopentene, 4-bromoheptene, 4-chloroheptene,4-fluoroheptene, cis- and trans-1,2-dichloroethylenes,1,2-dibromoethylene, 1,2-difluoroethylene, 1,2-diiodoethylene,chloroethylene (vinyl chloride), 1,1-dichloroethylene (vinylidenechloride), bromoethylene, fluoroethylene, iodoethylene,1,1-dibromoethylene, 1,1-fluoroethylene, 1,1-diiodoethylene,1,1,2,2-tetrafluoroethylene, 1-chloro-2,2,2-trifluoroethylene,chlorobutadiene and other halogenated diolefinic compounds;

3. Esters of organic and inorganic acids, such as vinyl acetate, vinylpropionate, vinyl butyrate, vinyl isobutyrate, vinyl valarate, vinylcaproate, vinyl enanthate, vinyl benzoate, vinyl toluate, vinylp-chlorobenzoate, vinyl-o-chlorobenzoate and similar vinylhalobenzoates, vinly-p-methoxybenzoate, vinyl-o-methoxybenzoate,vinyl-p-ethoxybenzoate, methyl metha crylate, ethyl methacrylate, propylmethacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate,heptyl methacrylate, heptyl methacrylate, octyl methacrylate, decylmethacrylate, methyl crotonate, and ethyl tiglate;

Methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate,butyl acrylate, isobutyl acrylate, amyl acrylate, hexyl acrylate,2-ethylhexyl acrylate, heptyl acrylate, octyl acrylate,3,5,5-trimethylhexyl acrylate, decyl acrylate, and dodecyl acrylate;

Isopropenyl acetate, isopropenyl propionate, isopropenyl butyrate,isopropenyl isobutyrate, isopropenyl valerate, isopropenyl caproate,isopropenyl enanthate, isopropenyl benzoate, isopropenylp-chlorobenzoate, isopropenyl o-chlorobenzoate, isopropenylo-bromobenzoate, isopropenyl m-chlorobenzoate, isopropenyl toluate,isopropenyl alpha-chloroacetate and isopropenyl alpha-bromopropionate;

Vinyl alpha-chloroacetate, vinyl alpha-bromoacetate, vinylalpha-chloropropionate, vinyl alpha-bromopropionate, vinylalpha-iodopropionate, vinyl alpha-chlorobutyrate, vinylalpha-chlorovalerate and vinyl alpha-bromovalerate;

Allyl chloride, allyl cyanide, allyl bromide, allyl fluoride, allyliodide, allyl chlorocarbonate, allyl nitrate, allyl thiocyanate, allylformate, allyl acetate, allyl propionate, allyl butyrate, allylvalerate, allyl caproate, allyl-3,5,5-trimethyl hexoate, allyl benzoate,allyl acrylate, allyl crotonate, allyl oleate, allyl chloroacetate,allyl trichloroacetate, allyl chloropropionate, allyl chlorovalerate,allyl lactate, allyl pyruvate, allyl aminoacetate, allyl acetoacetate,allyl thioacetate, as well as methallyl esters corresponding to theabove allyl esters, as well as esters from such alkenyl alcohols asbeta-ethyl allyl alcohol, beta-propyl allyl alcohols, 1-butene-4-ol,2-methyl-butene-4-ol, 2(2,2-dimethylpropyl)-1-butene-4-ol, and1-pentene-4-ol;

Methyl alpha-chloroacrylate, methyl alpha-bromoacrylate, methylalpha-fluoroacrylate, methyl alpha-iodoacrylate ethyl alpha,chloroacrylate, propyl alpha-chloroacrylate, isopropylalpha-bromoacrylate, amyl alpha-chloroacrylate, octylalpha-chloroacrylate, 3,5,5-trimethylhexyl alpha-chloroacrylate, decylalpha-chloroacrylate, methyl alpha-cyanoacrylate, ethylalpha-cyanoacrylate, amyl alpha-cyanoacrylate and decyl alpha-cyanoacrylate;

Dimethyl maleate, diethyl maleate, diallyl maleate, dimethyl fumarate,diethyl fumarate, dimethallyl fumarate and diethyl glutaconate;

4. Organic nitriles, such as acrylonitrile, methacrylonitrile,ethacrylonitrile, 3-octenenitrile, crotonitrile, oleonitrile, and thelike.

In carrying out the polymerization reaction, techniques well known inthe art may be employed. A peroxygen type catalyst is ordinarilyutilized. Diazo compounds or redox catalyst systems can also be employedas catalysts.

The acrylic polymer may likewise be prepared with monomers of the typesuch that the final polymer contains potential crosslinking sites. Suchmonomers include acrylamides or methacrylamides, their N-methylol orN-methylol ether derivatives; unsaturated monomers containing cappedisocyanate groups, or aziridyl groups; and hydroxy-containingunsaturated monomers, for example, hydroxyalkyl acrylates.

Another method of producing acrylic polymers which may be utilized inthis invention is to react an acrylic polymer containing reactive sites,such as carboxyl groups or hydroxyl groups, secondary amine groups orother active hydrogen-containing sites, with an epoxy-containingcompound such as the diglycidyl ether of Bisphenol A or otherpolyepoxides as enumerated elsewhere herein, to provide an epoxygroup-containing acrylic polymer.

Vinyl addition polymers which contain alicyclic unsaturation can beepoxidized to form an epoxy group-containing polymer.

Yet another class of polymers which are useful in preparing the resinsof this invention are isocyanate group-containing polyurethanes. Theisocyanate-terminated polyurethane prepolymers employed as startingmaterials according to the present invention may be obtained by thereaction of a selected polymeric glycol. The polyurethane polymersinclude those which are prepared from polyalkylene ether glycols anddiisocyanates. The term "polyalkylene ether glycol" as used hereinrefers to a polyalkylene ether which contains terminal hydroxy groups.They are sometimes known as polyoxyalkylene glycols, polyalkyleneglycols, or polyalkylene oxide glycols, or dihydric polyoxyalkylenes.Those useful in preparing the products of this invention may berepresented by the formula HO(RO)_(n) H, in which R stands for analkylene radical and n is an integer. Glycols containing a mixture ofradicals, as in the compound HO(CH₂ OC₂ H₄ O)_(n) H, or HO(C₂ H₄ O)_(n)(C₃ H₆ O)_(m) (C₂ H₄ O)_(n) H, can be used. These glycols are eitherviscous liquids or waxy solids. Polytetramethylene ether glycols, alsoknown as polybutylene ether glycols, may be employed. Polyethylene etherglycols and poly-propylene ether glycols, having the above-indicatedformula, are among the preferred glycols. The presently preferredglycols are polypropylene glycols with a molecular weight between about300 and about 1,000.

Any of a wide variety of organic polyisocyanates may be employed in thereaction, including aromatic aliphatic, and cycloaliphatic diisocyanatesand combinations of these types.

Instead of the hydrocarbon portion of the polyether glycols used informing the polyurethane products being entirely alkylene, it cancontain arylene or cycloalkylene radicals together with the alkyleneradicals as, for example, in the condensation product of a polyalkyleneether glycol with alpha, alpha'-dibromo-p-xylene in the presence ofalkali. In such products, the cyclic groups inserted in the polyesterchain are preferably phenylene, naphthylene or cyclohexylene radicals orthose radicals containing alkyl or alkylene substituents, as in thetolylene, phenylethylene or xylene radicals.

Also included in the polyurethane products are those made from asubstantially linear polyester and an organic diisocyanate of thepreviously described type. Products of this sort are described in U.S.Pat. Nos. 2,621,166; 2,625,531; and 2,625,532. The polyesters areprepared by reacting together glycols and dicarboxylic acids. Anotheruseful group of compounds for this purpose are the polyester amideresins having terminal hydroxyl groups. The preferred polyesters may berepresented by the formula HO--B--OOC--B'--COO_(n) --BOH, in which B andB' are hydrocarbon radicals derived from the glycol and dicarboxylicacid respectively and n is an integer. In the preparation of thesepolyesters, the glycol is used in at least slight excess so that thepolyesters contain terminal hydroxyl groups which are available forreaction with the isocyanates. The same polyisocyanates and reactionconditions useful in preparing polyurethanes from the polyalkylene etherglycols are also useful with the polyesters.

Polyurethane glycols may also be reacted with an organicpolyisocyanate-terminated polyurethanes for use as starting materials inthe presnet invention. The starting polyurethane glycol is prepared byreacting a molar excess of a polymeric glycol with an organicdiisocyanate. The resulting polymer is a polyurethane containingterminal hydroxyl groups which may then be further reacted withadditional polyisocyanate to produce the starting isocyanate-terminatedpolyurethane prepolymer.

Another starting polyurethane prepolymer may be such as disclosed inU.S. Pat. No. 2,861,981, namely, those prepared from a polyisocyanateand the reaction product of an ester of an organic carboxylic acid withan excess of a saturated aliphatic glycol having only carbon atoms inits carbon chain and a total of 8 to 14 carbon atoms, at least onetwo-carbon branch per molecule, and having terminal hydroxy groupsseparated by at least six carbon atoms.

It is obvious, from the above-described methods by which thepolyurethane reaction products may be prepared and from the reactantsused, that these products will contain a plurality of intralinearradicals of the formula --NH--CO--O--X--O--CO--NH--, wherein thebivalent radical --O--X--O-- is obtained by removing the terminalhydrogen atoms of the polymeric glycol, said glycol being selected fromthe group consisting of polyalkylene ether glycols, polyurethaneglycols, polyalkylene arylene ether glycols, polyalkylenecycloalkyleneether glycols, polyalkylene ether-polythioether glycols, polyester amideglycols of the formula:

    HO--[B--O--CO--B'--CO--O].sub.n --B--OH

where B and B' are hydrocarbon radicals and n is an integer, and that atypical isocyanate-terminated polyurethane polymer produced fromdiisocyanates and dihydric glycols will, on an average, contain (at a2:1 NCO:OH ratio) a plurality of intralinear molecules conforming to theformula:

    OCN--Y--NH--CO--O--X--O--CO--NH--Y--NCO

wherein --O--X--O has the value given previously and Y is thepolyisocyanate hydrocarbon radical.

In the preparation of the starting polyurethane polymer, an excess ofthe organic polyisocyanate of the polymeric glycol is used, which may beonly a slight excess over the stoichiometric amount (i.e., oneequivalent of polyisocyanate for each equivalent of the polymericglycol). In the case of a diisocyanate and a dihydric polyalkyleneether, the ratio of NCO to OH of the polyol will be at least one and maybe up to a 3:1 equivalent ratio. The glycol and the isocyanate areordinarily reacted by heating with agitation at a temperature of 50°C.to 130°C., preferably 70°C. to 120°C. The ratio of organicpolyisocyanate compound to polymeric glycol is usually and preferablybetween about 1.3:1 and 2.0:1.

The reaction is preferably, but not necessarily, effected in the absenceof a solvent, when the prepolymer is a fluid at processing temperatures.When it is not, or when it is desired to employ a solvent, convenientsolvents are inert organic solvents having a boiling range above about90°C. when the reaction is to be carried out in open equipment. Lowerboiling solvents may, of course, be used where the reaction is carriedout in closed equipment to prevent boiling off the solvent at thetemperatures of the reaction. Solvents boiling at substantially morethan 140°C. are difficult to remove from a final chain-extendedelastomer at desirable working temperature, although it will be obviousthat higher boiling solvents may be employed where the excess solvent isremoved by means other than by heating or distillation. The solvent,when used, may be added at the beginning, at an intermediate point, orat the end of the prepolymer reaction stage, or after cooling of theformed prepolymer. The solvents to be used are preferably those in whichthe reactants have some solubility but in which the final chain-extendedproduct is insoluble. Ketones, tertiary alcohols and esters may be used.The aliphatic hydrocarbon solvents such as the heptanes, octanes andnonanes, or mixtures of such hydrocarbons obtained fromnaturally-occurring petroleum sources such as kerosene, or fromsynthetically prepared hydrocarbons, may sometimes by employed.Cycloaliphatic hydrocarbons such as methylcyclohexane and aromatichydrocarbons such as toluene may likewise be used. Toluene and isopropylacetate are preferred solvents. The amount of solvent used may be variedwidely. From 25 to 400 parts of solvent per 100 parts of glycol havebeen found to be operable. The excess solvent, where large amounts areemployed, may be separated partially or completely from the polymerprior to emulsification in the water solution. If an emulsion techniqueis to be employed in the chain extension, sometimes the excess solventis useful and is allowed to remain during the emulsification stage.

The reactants are cooked for a period sufficient to react most, if notall, of the hydroxy groups, whereafter the prepolymer is allowed tostand and the free NCO content determined.

Usual pHs are employed during preparation of the prepolymer, thereaction preferably being maintained substantially neutral. Basesaccelerate the reaction, acids retard the reaction, and preferablyneither are added.

These isocyanate group-containing polyurethanes are then reacted withepoxy-containing compound such as glycidol, for example, at temperaturesof about 25°C. to about 45°C., usually in the presence of a catalystwhich promotes urethane formation.

In the process of the invention, the epoxy group-containing compound isreacted with a material selected from the group consisting of aminesalts, phosphine-acid mixtures and sulfide-acid mixtures to formquaternary onium salt group-containing resins.

The process of this invention can be used to produce essentially epoxygroup-free resins as well as epoxy group-containing resins. Where theepoxide is reacted with at least about a stoichiometric amount of aminesalt, sulfide or phosphine, essentially epoxide group-free resins areproduced; where resin containing free epoxide groups are desired, theratio of starting polyepoxide to amine salt, sulfide or phosphine isselected so as to provide an excess of epoxy groups, thereby producing aresin containing free unreacted epoxide groups. Epoxy-free resin canalso be provided by hydrolysis or post reaction of the epoxide reactionproduct.

Examples of amine salts which may be employed include salts of ammonia;primary, secondary and tertiary amines, and preferably tertiary amines;salts of boric acid or an acid having a dissociation constant greaterthan that of boric acid and preferably an organic acid having adissociation constant greater than about 1 × 10⁻ ⁵. The presentlypreferred acid is lactic acid. Such acids include boric acid, lacticacid, acetic acid, formic acid, propionic acid, butyric acid,hydrochloric acid, phosphoric acid and sulfuric acid. The amines may beunsubstituted amines or amines substituted with nonreactive constituentssuch as halogens or hydroxylamines. Specific amines includedimethylethanolamine, salts of boric, lactic, propionic, formic,butyric, hydrochloric, phosphoric and sulfuric, or similar salts intriethylamine, diethylamine, trimethylamine, diethylamine,dipropylamine, 1-amino-2-propanol, and the like. Also included areammonimum phosphate, as well as other amine and ammonium salts asdefined above.

A distinct class of amine compounds within the broader class is aminecontaining one or more secondary or tertiary amino groups and at leastone hydroxyl group.

In most cases, the hydroxyl amine employed corresponds to the generalformula: ##EQU2## where R₁ and R₂ are, preferably, methyl, ethyl orlower alkyl groups, but can be essentially any other organic radical, solong as they do not interfere with the desired reaction. Benzyl,alkoxyalkyl and the like are examples. R₁ can also be hydrogen. Thenature of the particular groups is less important that the presence of asecondary or tertiary amino nitrogen atom, and thus higher alkyl, aryl,alkaryl, aralkyl, and substituted groups of the types can be present.The group represented by R₃ is a divalent organic group, such asalkylene or substituted alkylene, e.g., oxyalkylene orpoly(oxyalkylene), or even arylene, alkarylene or substituted arylene.R₃ can also be an unsaturated group, e.g., an alkylene group such as##EQU3## Other groups represented by R₃ include cyclic or aromaticgroups. One type of useful amine, for instance, is represented by theformula: ##SPC1##

where n is 1 to 3. Dialkanolamines, of the general formula R₁ N(R₃ OH)₂,and trialkanolamines, of the general formula N(R₃ OH)₃, are also useful.

Some examples of specific amines are as follows: dimethylethanolamine,dimethylpropanolamine, dimethylisopropanolamine, dimethylbutanolamine,diethylethanolamine, ethylethanolamine, methylethanolamine,N-benzylethanol-amine, diethanolamine, triethanolamine,dimethylaminomethyl phenol, tris(dimethylaminomethyl)phenol,2-[2(dimethylamino)ethoxy] ethanol,1-[1-(dimethylamino)-2-propoxy]-2-propanol,2-(2-[2-dimethylamino)ethoxy]ethoxy)ethanol,1-[2-(dimethylamino)ethoxy]-2-propanol,1-(-1[dimethylamino)-2-propoxy]-2-propoxy)-2-propanol, benzyl dimethylamine.

Another distinct class of amine compound within the broader class is anamine containing one or more secondary or tertiary amino groups and##EQU4## where R₁ and R₂ are each preferably methyl, ethyl, or otherlower alkyl groups, but can be essentially any other organic radical, solong as they do not interfere with the desired reaction. Benzyl,alkoxyalkyl, and the like are examples. R₁ can also be hydrogen. Thenature of the particular groups is less important than the presence of asecondary or tertiary amino nitrogen atom, and thus higher alkyl, aryl,alkaryl, and substituted groups of these types can be present. The grouprepresented by R₃ is a divalent organic group, such as alkylene orsubstituted alkylene, e.g., oxyalkylene or poly (oxyalkylene), or lessdesirably, arylene, alkarylene or substituted arylene. R₃ can also be anunsaturated group, e.g., an alkylene group.

Such amines can be prepared by known methods. For example, an acidanhydride, such as succinic anhydride, phthalic anhydride or maleicanhydride, can be reacted with an alkanolamine, such asdimethylethanolamine or methyldiethanolamine; the group represented byR₃ in the amines produced in such cases contain ester groups. Othertypes of amines are provided, for example, by reacting an alkylaminewith an alkyl acrylate or methacrylates such as methyl or ethyl acrylateor methacrylate, as described in U.S. Pat. No. 3,419,525. Preferably,the ester group is subsequently hydrolyzed to form a free carboxylgroup. Other methods for producing amines of different types can also beemployed.

It can be seen that the groups represented by R₃ can be of widelyvarying types. Some examples are: --R'--, --R'OCOR'--, and --R'O)_(n)COR'--, where each R' is alkylene, such as --CH₂ CH₂ --, ##EQU5## etc.,or alkenylene, such as --CH=CH--such as --CH=CH--, and n is 2 to 10 orhigher. Other groups represented by R' include cyclic or aromaticgroups.

Some examples of specific amines are as follows:

N,n-dimethylaminoethyl hydrogen maleate

N,n-diethylaminoethyl hydrogen maleate

N,n-dimethylaminoethyl hydrogen succinate

N,n-dimethylaminoethyl hydrogen phthalate

N,n-dimethylaminoethyl hydrogen hexahydrophthalate

2-(2-dimethylaminoethyoxy ethyl hydrogen maleate

1-methyl-2-(2-dimethylaminoethoxy) ethyl hydrogen maleate

2-(2-dimethylaminoethoxy) ethyl hydrogen succinate

1,1-dimethyl-2-(2-dimethylaminoethoxy) ethyl hydrogen succinate

2-[2-(2-dimethylaminoethoxy) ethoxy] ethyl hydrogen maleate

beta-(dimethylamino)propionic acid

beta-(dimethylamino)isobutyric acid

beta-(diethylamino)propionic acid

1-methyl-2-(dimethylamino)ethyl hydrogen maleate

2-(methylamino)ethyl hydrogen succinate

3-(ethylamino)propyl hydrogen maleate

2[2-(dimethylamino)ethoxy]ethyl hydrogen adipate

N,n-dimethylaminoethyl hydrogen azelate

di(N,N-dimethylaminoethyl)hydrogen tricarballylate

N,n-dimethylaminoethyl hydrogen itaconate

1-(1-[1(dimethylamino)-2-propoxy]-2-propoxy)-2-propyl hydrogen maleate

2-[2-(2-[2-(dimethylamino)ethoxy]ethoxy)ethoxy]ethyl hydrogen succinate.

In one embodiment, the epoxy compounds described above may be reactedwith an ester of boric acid or a compound which can be cleaved to formboric acid in a medium containing water and preferably anaminocontaining boron ester and/or a tertiary amine salt of boric acidto produce the epoxy reaction products. The boron compound componentutilized in producing the reaction products can be, for example, anytriorganoborate in which at least one of the organic groups issubstituted with an amino group. Structurally, such esters of boric acidor a dehydrated boric acid such as metaboric acid and tetraboric acid,although not necessarily produced from such acids. In most cases theboron esters employed correspond to one of the general formulas:##EQU6## where the R groups are the same or different organic groups.The groups represented by R above can be virtually any organic group,such as hydrocarbon or substituted hydrocarbon, usually having not morethan 20 carbon atoms and preferably not more than about 8 carbon atoms.The preferred esters have alkyl groups or polyoxyalkyl groups. At leastone of the organic groups contain an amine group, i.e., a group of thestructure; ##EQU7## where R₁ and R₂ are hydrogen or preferably methyl,ethyl or other lower alkyl groups, but can be essentially any otherorganic radical, so long as they do not interfere with the desiredreaction. The nature of the particular groups is less important than thepresence of an amino nitrogen atom, and thus higher alkyl, aryl,alkaryl, aralkyl and substituted groups of these types can be present.While both R₁ and R₂ can be hydrogen (i.e., the amino group is a primaryamino group), it is preferred that at least one be an alkyl or otherorganic group, so that the amino group is secondary or tertiary.

The preferred boron esters correspond to the formula: ##EQU8## where Xhas the structure: ##EQU9## R₃ and R₄ being divalent organic radicals,such as alkylene or substituted alkylene, e.g., oxyalkylene orpoly(oxyalkylene), or less desirably, arylene, alkarylene or substitutedarylene. R₅ and R₆ can be alkyl, substituted alkyl, aryl, alkaryl, orother residue from essentially any monohydroxy alcohol derived byremoval of the hydroxyl group. R₅ and R₆ can be the same or different.

Examples of boron esters within the above class include:

2-(beta-dimethylaminiosopropoxy)-4,5-dimethyl-1,3,2-dioxaborolane

2-(beta-diethylaminoethoxy)-4,4,6-trimethyl- 1,3,2-dioxaborinane

2-(beta-dimethylaminoethoxy)-4,4,6-trimethyl-1,3,2-dioxaborinane

2-(beta-diisopropylaminoethoxy-1,3,2-dioxaborinane

2-(beta-dibutylaminoethoxy)-4-methyl-1,3,2-dioxaborinane

2-(beta-diethylaminoethoxy)-1,3,2-dioxaborinane

2-(gamma-aminopropoxy)-4-methyl-1,3,2-dioxaborinane

2-(beta-methylaminoethoxy)-4,4,6-trimethyl-1,3,2-dioxaborinane2-(beta-ethylaminoethoxy)-1,3,6-trioxa-2-boracyclooctane

2-(gamma-dimethylaminopropoxy)-1,3,6,9-tetraoxa-2-boracycloundecane

2-(beta-dimethylaminoethoxy)-4-4(4-hydroxybutyl)-1,3,2-dioxaborolaneReaction product of (CH₃)₂ NCH₂ CH₂ OH + Lactic acid +B₂ O₃ + neopentylglycol.

A number of such boron esters are known. Many are described, forexample, in U.S. Pats. Nos. 3,301,804 and 3,257,442. They can beprepared by reacting one mole of boric acid (or equivalent boric oxide)with at least 3 moles of alcohol, at least one mole of the alcohol beingan aminosubstituted alcohol. The reaction is ordinarily carried out byrefluxing the reactants with removal of the water formed.

The amine salts and the epoxy comound are reacted by mixing thecomponents, preferably in the presence of a controlled amount of water.The amount of water employed should be that amount of water which allowsfor smooth reaction. Typically, the water is employed on the basis ofabout 1.75 percent to about 20 percent by weight based on the totalreaction mixture solids and preferably about 2 percent to about 15percent by weight, based on total reaction solids.

Another measure of the amount of water which may be employed is theequivalent ratio of water to amine nitrogen present in the reactionmixture. Typically the equivalent ratio of water to amine nitrogen iscontrolled between about 1.3 and about 16 equivalents of water perequivalent of amine nitrogen. Preferably, the ratio of water to aminenitrogen is controlled between about 1.5 and about 10.6 equivalents ofwater per equivalent of amine nitrogen.

The reaction temperature may be varied between about the lowesttemperature at which the reaction reasonably proceeds, for example, roomtemperature, or in the usual case, slightly above ordinary roomtemperature to a maximum temperature between about 100°C. and about110°C.

A solvent is not necessary, although one is often used in order toafford better control of the reaction. Aromatic hydrocarbons ormonoalkyl ethers of ethylene glycol are suitable solvents.

The proportions of the amine salt and the epoxy compound can be variedand the optimum proportions depend upon the particular reactants.Ordinarily, however from about one part to about 50 parts by weight ofthe salt per 100 parts of epoxy compound are employed. The proportionsare usually chosen with reference to the amount of nitrogen, which istypically from about 0.05 to about 16 percent based on the total weightof the amine salt and the epoxy compound. Since the amine salt reactswith the epoxide groups of the epoxy resin employed, in order to providean epoxy group-containing resin, the stoichiometric amount of amineemployed should be less than the stoichiometric equivalent of theepoxide groups present, so that the final resin is provided with oneepoxy group per average molecule.

Phosphonium group containing resins can be prepared by reacting theabove epoxy compounds with a phosphine in the presence of an acid toform quaternary phosphonium base group containing resins.

The phosphine employed may be virtually any phosphine which does notcontain interferring groups. For example, the phosphine may bealiphatic, aromatic or alicyclic. Examples of such phosphines includelower trialkyl phosphine, such as trimethyl phosphine, triethylphosphine, tripropyl phosphine, tributyl phosphine, mixed lower alkylphenyl phosphines such as phenyl dimethyl phosphine, phenyl diethylphosphine, phenyl dipropyl phospine, diphenyl methyl phosphine, diphenylethyl phosphine, diphenyl propyl phosphine, triphenyl phosphine,alicyclic phosphines such as tetramethylene methyl phosphine and thelike.

The acid employed may be virtually any acid which forms a quaternaryphosphonium salt. Preferably the acid is an organic carboxylic acid.Examples of the acids which may be employed are boric acid. lactic acid,formic acid, acetic acid, propionic acid, butyric acid, hydrochloricacid, phosphoric acid, and sulfuric acid. Preferably the acid is an acidhaving a dissoaiation constant greater than about 1 × 10⁻ ⁵.

The ratio of phosphine to acid is not unduly critical. Since one mole ofacid is utilized to form one mole of phosphonium group, it is preferredthat at least about one mole of acid be present for each mole of desiredphosphine-to-phosphonium conversion.

The phosphine/acid mixture and the epoxy compound are reacted by mixingthe components, sometimes at moderately elevated temperatures. Thereaction temperature is not unduly critical and is chosen depending uponthe reactants and their rates. Frequently the reaction proceeds well atroom temperature or temperatures up to 70°C., if desired. In some cases,temperatures as high as about 110°C. or higher may be employed. Theproportions are usually chosen with reference to the amount ofphosphine, which is typically from about 0.1 to about 35 percent basedon the total weight of the phosphine and the epoxy compound.

Sulfonium group containing resins can be prepared by reacting the aboveepoxy compounds with a sulfide in the presence of an acid to formquaternary sulfonium base group containing resins.

The sulfide employed may be virtually any sulfide which reacts withepoxy groups and which does not contain interfering groups. For example,the sulfide may be aliphatic, mixed aliphatic-aromatic, aralkyl orcyclic. Examples of such sulfides include dialkyl sulfides such asdiethyl sulfide, dipropyl sulfide, dibutyl sulfide, dihexyl sulfide,phenyl sulfide or alkyl phenyl sulfides such as diphenyl sulfide, ethylphenyl sulfide, alicyclic sulfides such as tetramethylene sulfide,pentamethylene sulfide, hydroxyl alkyl sulfides such as thiodiethanol,thiodipropanol, thiodibutanol and the like.

The acid employed may be virtually any acid which forms a quaternarysulfonium salt. Preferably the acid is an organic carboxylic acid.Examples of acids which may be employed are boric acid, formic acid,lactic acid, acetic acid, propionic acid, butyric acid, hydrochloricacid, phosphoric acid and sulfuric acid. Preferably the acid is an acidhaving a dissociation constant greater than about 1 × 10⁻ ⁵.

The ratio of sulfide to acid is not unduly critical. Since one mole ofacid is utilized to form one mole of sulfonium group, it is preferredthat at least about one mole of acid be present for each mole of desiredsulfide-to-sulfonium conversion.

The sulfide/acid mixture and the epoxy compound are reacted by mixingthe components, usually at moderately elevated temperatures such as70°-110°C. A solvent is not necessary, although one is often used inorder to afford better control of the reaction. Aromatic hydrocarbons,monoalkyl ethers of ethylene glycol, aliphatic alcohols are suitablesolvents. The proportions of the sulfide to the epoxy compound can bevaried and the optimum proportions depend upon the particular reactants.Ordinarily, however, from about one part to about 50 parts be weight ofthe sulfide per 100 parts of epoxy compound is employed. The proportionsare usually chosen with reference to the amount of sulfur, which istypically from about 0.1 to about 25 percent, based on the total weightof the sulfide and the epoxy compound.

Since the sulfide or phosphine react with the epoxy group, where epoxygroup-containing products are desired, less than an equivalent ofsulfide or phosphine should be employed so that the resultant resin hasone epoxy group per average molecule.

Where it is desired to incorporate boron into the resin molecule, onemethod is to incorporate boron by means of an amine borate ornitrogen-containing ester as described in copending application Ser. No.100,825, filed Dec. 22, 1970, the disclosure of which is herebyincorporated by reference. The boron compound reacts with availableepoxy groups to provide quaternary ammonium borate groups in the resinmolecule.

The reaction of the boron compound may be concluded simultaneously withsulfonium or phosphonium group formation since the reaction conditionsare similar.

The particular reactants, proportions and reaction conditions should bechosen in accordance with considerations well known in the art, so as toavoid gelation of the product during the reaction. For example,excessively severe reaction conditions should not be employed.Similarly, compounds having reactive substituents should not be utilizedalong with epoxy compounds with which those substituents might reactadversely at the desired conditions.

The pigment dispersant of the invention comprises the above-describedonium salt group solubilized resin where the ratio of quaternary oniumsalt in the resin to free epoxy groups in the precursor resin is greaterthan about 0.4 to 1 and preferably greater than 0.6 to 1. While thepigment dispersant is termed an epoxy resin, when the ratio of oniumgroups to epoxy groups is 1 to 1, essentially all the epoxy groups arereacted and the resin is essentially epoxy free. It has also been foundthat the presence of boron or a boron-type compound adversely affectsthe stability of the resultant paste. Accordingly, for most purposes, itis preferred that the use of boron be avoided.

The aqeuous pigment pastes of the invention are prepared by grinding ordispersing a pigment in the presence of an aqueous dispersion of theabove-described pigment dispersant in a manner well known in the art.

The pigment paste comprises as essential ingredients the dispersant andat least one pigment; however, the paste may, in addition, contain otheradjuvants such as plasticizers and the like, or wetting agents,surfactants or defoamers.

The pigment and dispersant may be ground in the conventional manner suchas in a steel ball mill, attritor, or sand mill.

The pigment and dispersant ratios vary from pigment to pigment over awide range, usually from about 2 percent to about 50 percent by weightof dispersant, based on pigment weight, may be used.

The final electrodepositable composition may contain, in addition to thepigment dispersion and an onium or amine salt group solubilized cationicelectrodepositable vehicle resin, crosslinking resins, solvents,antioxidants, surfactants, and other adjuvants typically employed in theelectrodepositable composition.

A number of amine group-containing, acid-solubilized, cationicelectrodepositable resins are known in the art and need not be describedin detail. Virtually any polyamine group-containing resin which can beacid-solubilized may be employed as an aqueous coating composition.Preferably the resin also contains hydroxyl groups. These resins includemulticomponent resin systems which contain two essential components, forexample, a polyamine group-containing resin together with a fully cappedorganic polyisocyanate described in copending applications Ser. Nos.47,917 filed June 19, 1970, and 193,590 filed Oct. 28, 1971, which arehereby incorporated by reference; as well as in systems containing anessentially self-curing resin system, for example, resin containingamine groups, hydroxyl groups and capped isocyanate groups within thesame molecule, where the capped isocyanate groups are stable at roomtemperature in the presence of hydroxyl or amine groups but reactivewith hydroxyl groups at elevated temperatures. Preferably, theisocyanate groups are capped with an aliphatic alkyl, alkoxyalkyl,cycloaliphatic alkyl, or aromatic alkyl monoalcohol or an oxime.Preferably, the resin contains about 0.5 to about 2.0 latent isocyanategroups per hydroxyl group. Resins within this class are described incopending Applications Ser. No. 193,591, filed Oct. 28, 1971, and Ser.No. 203,875, filed Dec. 1, 1971, which are hereby incorporated byreference.

The preferred vehicle resins are onium base salt solubilized cationicresins preferably containing epoxy groups. These resins arecharacterized quaternary onium group solubilized resins, preferablycontaining epoxy groups and optionally containing oxyalkylene groupsand/or compounds of boron. Preferably these resins are solubilized by asalt of an acid having a dissociation constant greater than 1 × 10⁻ ⁵.Resins and electrodepositable compositions of this type are described indetail in copending applications Ser. Nos. 167,470, filed July 29, 1971,167,476, filed July 29, 1971; 210,141, filed Dec. 20, 1971, and 217,278,filed Jan. 12, 1972, all of which are hereby incorporated by reference.

Enough pigment paste is used so that the final electrodepositablecomposition has the desirable properties. In most instances, the finalelectrodepositable composition has a pigment-to-binder ratio of betweenabout 0.05 and about 0.5.

In electrodeposition processes employing the aqueous coatingcompositions described above, the aqueous composition is placed incontact with an electrically-conductive anode and anelectrically-conductive cathode in an electric circuit. While in contactwith the bath containing the coating composition, an adherent film ofthe coating composition is deposited on the cathode. This is in contrastto processes utilizing polycarboxylic acid resins which deposit on theanode, and many of the advantages described above are in large partattributed to this cathodic deposition.

The conditions under which the electrodeposition is carried out are, ingeneral, similar to those used in electrodeposition of other types ofcoatings. The applied voltage may be varied greatly and can be, forexample, as low as one volt or as high as several thousand volts,although typically between 50 volts and 500 volts. The current densityis usually between about 1.0 ampere and 15 amperes per square foot, andtends to decrease during electrodeposition.

The method of the invention is applicable to the coating of anyelectrically-conductive substrate, and especially metals such as steel,aluminum, copper or the like.

After deposition, the coating is cured at elevated temperatures by anyconvenient method such as in baking ovens or with banks of infrared heatlamps.

Illustrating the invention are the following examples, which are not tobe construed as limiting the invention to their details. All parts andpercentages in the examples, as well as throughout this specificationare by weight unless otherwise specified.

EXAMPLE A

A dimethylethanolamine lactate was prepared by mixing 13.3 parts ofdimethylethanolamine and 18.0 parts of lactic acid (85 percent solutionin water). The mixture was held at 40°C. to 60°C. for a short time andthere was then added 7.2 parts of isopropanol. The final compositioncomprised 75 percent solids and contained 7.1 percent water.

EXAMPLE B

Into a reactor equipped with thermometer, stirrer, distillationapparatus with reflux and water trap, and means for providing an inertgas blanket where charged 741.6 parts of dimethylethanolamine, 714 partslactic acid and 300 parts toluene. The reaction mixture was heated tobetween 105°C. and 110°C. for 4 hours. A total of 120 parts of waterwere collected with an index of refraction of n_(D) ²⁵ 1.377. There wasthen added 245 parts of boric oxide, 728 parts neopentyl glycol. Thereaction mixture was heated between 115°C. and 128°C. for approximatelyfour hours, collecting an additional 205 parts of water of reactionn_(D) ²⁵ 1.386. The reaction product had a percent nitrogen content of4.51 and has a proposed structure of: ##EQU10## This product ishereinafter referred to as the product of Example B.

EXAMPLE I

Into a reactor equipped with thermometer, stirrer, reflux condenser, andmeans for providing an inert gas blanket where charged 342.8 parts ofEpon 829 and 32.7 parts of Bisphenol A. The mixture was heated to170°C., at which time an exotherm occurred. The reaction mixture washeld at 180° C. to 185°C. for about 45 minutes. The reaction mixture wasthen cooled to 130°C. with the subsequent addition of 158.7 parts ofpolypropylene glycol with an average molecular weight of about 425.There was then added a small amount of dimethyl ethanolamine as acatalyst and the reaction mixture was held at 130°C. to 140°C. for about4 hours until the reaction mixture had a Gardner-Holdt viscosity of H toI, measured at 50 percent solids in a solvent comprising 90 percentisophorone and 10 percent toluene.

The reaction mixture was cooled to 130°C. and a small amount of formicacid added to neutralize the amine catalyst. The reaction product atthis point had an epoxy equivalent, adjusted to 100 percent solids of720. The reaction mixture was cooled to 90°C. and there was added 37.7parts of 2-ethylhexanol containing a small amount of Foam Kill 639, ananti-foaming agent.

At 80°C. there was added a mixture of 57.5 parts of the product ofExample B and 14.4 parts of isopropanol. This mixture was added over a20 minute period at a reaction temperature of 89°C. The reaction productwas held at 90°C. to 95°C. for five minutes after the addition wascomplete. There was then added 280 parts of deionized water. The producthad an epoxy equivalent of 1663 at 60.7 percent solids and had a ratioof quaternary to epoxy groups of 0.24:1.

EXAMPLE II

Into a reactor equipped with thermometer, stirrer, reflux condenser andmeans for providing inert gas blanket were charged 1062 parts of Epon829 and 181 parts of Bisphenol A. The mixture was heated to 170°C., atwhich time an exotherm occurred. The reaction mixture was held at 180°C.to 185°C. for 45 minutes. The reaction mixture was then cooled to 130°C.with the addition of 473 parts of polypropylene glycol with an averagemolecular weight of 600. There was then added 3.0 parts of dimethylethanolamine. The reaction mixture was held at 130°C. to 140°C. forabout 4.5 hours. The reaction mixture then had a Gardner-Holdt viscosityof L+, measured at 50 percent solids, the additional solvent comprising90 percent isophorone and 10 percent toluene. The reaction mixture atthis point was analyzed to have an epoxy equivalent (adjusted to 100percent solids) of 780 and a hydroxyl value (adjusted to 100 percentsolids) of 303.

To the reaction mixture was added a small amount of formic acid toneutralize the catalyst. The reaction mixture was cooled to 70°C. andthere was added a mixture of 731 parts of dimethyl ethanolamine, 158parts of 85 percent lactic acid and 68 parts of isopropanol. Thismixture was added at a temperature range of 70° to 100°C. over a20-minute period. After the reaction was completed, the reaction mixturewas held for 5 minutes at 100°C. There was then added 560 parts ofdeionized water and a mixture of 132 parts of 2-ethylhexanol and 9.7parts of Foam Kill 639, an antifoaming agent. There was then added anadditional 327 parts of water. The product contained a ratio of 0.69equivalent of quaternary nitrogen to one equivalent of epoxy.

EXAMPLE III

A first stage reaction product, the reaction of Epon 829 and Bisphenol Aand polypropylene glycol was prepared as in Example II. The reactionmixture, after formic acid addition to neutralize the catalyst, wascooled to 70°C. and there was added a mixture of 85 parts of dimethylethanolamine, 4 parts 85 percent lactic acid and 84 parts ofisopropanol. This mixture was added over a 20 minute period attemperatures of 70°C. to 100°C. The reaction mixture was held at 100°C.for an additional five minutes. There was then added 120 parts of2-ethylhexanol containing 9.2 parts of Foam Kill 639. There was thenadded an additional 800 parts of deionized water. The resultant producthad an epoxy equivalent, adjusted to 100 percent solids, of 2,500 and ahydroxyl value, adjusted to 100 percent solids, of 84.3. The resincontained a ratio of quaternary groups to epoxy groups of 0.41:1.

EXAMPLE IV

A first stage reaction product was prepared as in Example II. After thereaction of the Epon 829, Bisphenol A and polypropylene glycol, formicacid was added to neutralize the catalyst. The reaction mixture wascooled to 70°C. and there was added a mixture of 189 parts of dimethylethanolamine, 227 parts of 85 percent lactic acid and 95 parts ofisopropanol. This mixture was added over a 20-minute period at atemperature range of 70°C. to 100°C. The reaction mixture was held forfive minutes at 100°C. after the addition was complete. There was thenadded 500 parts of deionized water, 146 parts of 2-ethyl hexanolcontaining 10.3 parts of Foam Kill 639. There was then added anadditional 330 parts of deionized water. The epoxy equivalent of thereaction mixture was infinite and the reaction mixture had a hydroxylvalue, adjusted to 100 percent solids, of 72.8. The ratio of quaternarygroups to epoxy groups was 1:1.

EXAMPLE V

Into a reactor equipped with thermometer, stirrer, reflux condenser andmeans for providing an inert gas blanket were charged 330 parts of Epon829 and 112 parts of Bisphenol A. The reaction mixture was heated to170°C., at which time an exotherm occurred. The reaction mixture washeld at 180°C. to 185°C. for 45 minutes. The reaction mixture was cooledto 95°C. and there was added a mixture of 94.5 parts of the product ofExample A and 7.0 parts of water, the reaction temperature dropped to78°C. and the reaction mixture was cloudy. After 10 minutes, thereaction temperature had raised to 95°C. and the reaction mixturecleared. The reaction mixture was held at 95°C. for an additional 30minutes. There was then added an additional 150 parts of deionizedwater. The reaction product had an epoxy equivalent of 6,400 adjusted to100 percent solids and a hydroxyl value adjusted to 100 percent solidsof 125. The product had a quaternary-to-epoxy ratio of 0.48:1.

EXAMPLE VI

A first stage reaction product was prepared as in Examples II and III.There was added a solution of 180 parts of isopropanol, 96 parts of theproduct of Example B, over 20 minutes at a reaction temperature of 78°C.to 85°C. The product was held at 85°C. to 97°C. for an additional 5minutes after the reaction was complete. There was then added 300 partsof deionized water and a solution of 114 parts of 2-ethylhexanolcontaining 9 parts of Foam Kill 639. The final product had an epoxyequivalent, adjusted to 100 percent solids of 920 and a hydroxyl valueadjusted to 100 percent solids of 171. The product had aquaternary-to-epoxy ratio of 0.15:1.

EXAMPLE VII

A first stage reaction product was prepared as in Examples II and III.There was added a solution of 180 parts of isopropanol, 96 parts of theproduct of Example B, over 20 minutes at a reaction temperature of 78°C.to 85°C. The product was held at 85°C. to 97°C. for an additional 5minutes after the reaction was complete. There was then added 300 partsof deionized water and a solution of 114 parts of 2-ethylhexanolcontaining 9 parts of Foam Kill 639. The final product had an epoxyequivalent, adjusted to 100 percentsolids of 920 and a hydroxyl valueadjusted to 100 percent solids of 171. The product had aquaternary-to-epoxy ratio of 0.15:1.

EXAMPLE VIII

Into a reactor equipped with thermometer, stirrer, reflux condenser andmeans for providing an inert gas blanket were charged 1035 parts of Epon829 and 335 parts of Bisphenol A. The mixture was heated to 170°C. atwhich time an exotherm occurred. The reaction mixture was held at 180°C.to 185°C. for 40 minutes. The reaction mixture was then cooled to 130°C.There was added a mixture of 192 parts of 2-ethylhexanol containing 8.6parts of Foam Kill 639. To the reaction mixture at 110°C. was added amixture of 512 parts of the product of Example A and 100 parts ofdeionized water. The reaction temperature dropped with the addition to87°C. and the reaction mixture was milky. The reaction temperature wasraised to 90°C. and the reaction mixture cleared in 10 minutes. Thereaction mixture was held between 90°C. and 100°C. for an additional 30minutes. There was then added 92 parts of isopropanol and 175 parts ofdeionized water. The product had an infinite epoxy equivalent and had ahydroxyl value adjusted to 100 percent solids of 103. The productcontained a quaternary-to-epoxy ratio of 1:1.

EXAMPLE IX

Into a reactor equipped with thermometer, stirrer, reflux condenser andmeans for providing an inert gas blanket were charged 1062 parts of Epon829 and 181 parts of Bisphenol A. The mixture was heated to 150°C. atwhich time an exotherm occurred. The reaction mixture was held at 160°to 165°C. for about 45 minutes, after which time were added 474 parts ofpolypropylene glycol with an average molecular weight of 600. Thereaction mixture was then cooled to 130°C., at which time 3.3 parts ofdimethylethanolamine were added. The reaction mixture was held at 130°C.to 135°C. for about 5 hours and was then allowed to cool. To thereaction mixture at about 134°C. were added 123 parts of 2-ethylhexanoland 8.5 parts of Foam-Kill 639. To the reaction mixture of 107°C. wereadded 6.25 parts of 75 percent lactic acid. To the reaction mixture(temperature 100°C) were then added 239.2 parts of the product ofExample A and 224.5 parts of a 4.5 percent solution of boric acid. Thereaction temperature dropped with the addition to 90°C. and the reactionmixture was milky. The reaction temperature was raised to 96°C. and thereaction mixture cleared in 10 minutes. The reaction mixture was heldbetween 90° and 100°C. for an additional 10 minutes. There was thenadded 52 parts of a boric acid solution. The product had an epoxyequivalent of 2,570 and had an hydroxyl value of 60.1 at 76.1 percentsolids. The product contained a quaternary-to-epoxy ratio of 0.5:1.

EXAMPLE X

Into a reactor equipped with a thermometer, stirrer, reflux condenserand means for providing an inert gas blanket were charged 300 parts ofethylene glycol monobutyl ether. While the charge was being heated, onequarter of the following monomer feed was gradually added to thereactor:

    Monomer Feed       Parts by Weight                                            ______________________________________                                        Ethyl acrylate     330                                                        Methyl methacrylate                                                                              330                                                        2-Hydroxyethyl acrylate                                                                          180                                                        Glycidyl methacrylate                                                                            300                                                        Styrene            60                                                         Azo bis (isobutyronitrile)                                                                       18                                                         Tertiary dodecyl mercaptan                                                                       36                                                         ______________________________________                                    

The reaction mixture was heated to 150°C. at which time an exothermoccurred. The mixture was held at 145°C. for another 5 minutes at whichtime the addition of the initial one quarter of the monomer feed wascomplete. The reaction mixture was then cooled to about 125°C., at whichtime the rest of the monomer feed was gradually added thereto. Theaddition was complete after about 2 hours at which time the temperaturewas 137°C. The mixture was held at 125°C. to 135°C. for about 31/2 hoursand was then cooled to room temperature. Ionol 185 (polymerizationinhibitor available from Shell, Industrial Chemical Division) (1.2parts) was then added to the mixture.

Four-hundred and eighty parts of the resultant product were charged to asecond reactor, and heating was begun. When the temperature had reached95°C., 179 parts of thiodiethanol, 155 parts of 85 percent lactic acidand 100 parts of deionized water were added. The temperature wasmaintained at about 100°C. for about 45 minutes, after which the productwas allowed to cool. The product had an infinite epoxy equivalent, ahydroxyl value of 210, and consisted of 71 percent solids. The productcontained a quaternary-to-epoxy ratio of 1:1.

EXAMPLE XI

The following pigment pastes were all ground in conventional grindingequipment to a Hegmann Grind Gauge reading of 7+. Paste stability waschecked by storing the paste in a hot room at 110°F.

A. A paste was formed from 205.6 parts of the resin of Example I, 190.8parts of deionized water and 500 parts of titanium dioxide. Theresultant pigment paste was stored in a hot room over night. The nextmorning the paste had gelled.

B. A paste was formed from 205 parts of the resin of Example II, 533parts of titanium dioxide and 162 parts of deionized water, to yield apigment-binder ratio of 4:1 at 75 percent solids. The initial Brookfieldviscosity was 6,700 centipoises at 25°C. The paste was stored at 110°F.After 3 days, the viscosity was 6,700 centipoises; after 10 days --9,400 centipoises; 17 days -- 12,000 centipoises; 24 days -- 11,200centipoises; and 31 days -- 12,000 centipoises. The test wasdiscontinued.

C. A pigment paste was formed from 202 parts of the resin of ExampleIII, 526 parts of titanium dioxide and 172 parts of deionized water toyield a pigment-binder ratio of 4:1 and a solids content of 73 percent.The initial viscosity of the pigment paste was 4,000 centipoises. Uponstoring at 110°F., the following viscosities were observed: 3 days --4,800; 10 days -- 10,200; 17 days -- 52,000 24 days -- the pigment pastehad gelled.

D. A pigment paste was formed from 208 parts of the resin of Example IV,540 parts of titanium dioxide and 152 parts of deionized water to yielda pigment paste with a pigment-binder ratio of 4:1 at 75 percent solids.The pigment paste had an initial viscosity of 8,800 centipoises. Storageat 110°F., showed the following viscosities: 3 days -- 11,000centipoises; 10 days -- 11,400 centipoises; 17 days -- 12,000centipoises; 24 days -- 12,000 centipoises; 31 days -- 12,000centipoises. The test was discontinued.

E. A pigment paste was formed from 199 parts of the resin of Example V,540 parts of titanium dioxide and sufficient water to yield 72 percentsolids. The paste had a pigment-binder ratio of 4:1. The initialviscosity of the paste was 3,400 centipoises. After 7 days at 110°F.,the paste had gelled.

F. A pigment paste was formed from 188 parts of the resin of Example VI,560 parts of titanium dioxide and 211 of deionized water to yield apigment paste which had a pigment-binder ratio of 4:1 at 73 percentsolids. The paste gelled while grinding.

G. A pigment paste was formed from 200 parts of the resin of ExampleVII, 240 parts of deionized water, 490.2 parts of titanium dioxide, 54.5parts of china clay, 1.2 parts of red iron oxide, 12.2 parts of yellowiron oxide and 2 parts of carbon black. The pigment paste had an initialviscisith of 3,800 centipoises. After storage at 110°F., at the end ofthree days the paste displayed a viscosity of 69,000 centipoises and at11 days -- 336,000 centipoises.

H. The pigment paste of G was repeated, however, containing in addition14 parts of polypropylene glycol 600. The initial viscosity was 4,400.After three days, the pigment paste had a viscosity of 23,600centipoises; after 11 days -- 106,800.

I. A. pigment paste was formed from 143 parts of the resin of ExampleVIII, 171 parts of deionized water, 396 parts of titanium dioxide and 4parts of carbon black. The pigment paste had an initial viscosity of70,000 centipoises. After storage at 110°F., for two weeks, the pastehad gelled.

J. A pigment paste was formed from 195 parts of the resin of Example IX,330 parts of deionized water, 534 parts of titanium dioxide, 6 parts ofSyloid 161 (ethanolated alkyl guanadine, from American Cyanamid) and 6parts of Aersol C-61 (Grace Davison Chem.). After storage at 110°F., for31 days, the paste was still stable and the test was discontinued.

Other resins and pigment pastes can be formed using varied reactants andreaction conditions and constituents as set forth in the specificationto provide compositions which display pigment paste stabilities of animproved nature.

According to the provisions of the Ppatent statutes, there are describedabove the invention and what are now considered to be its bestembodiments. However, within the scope of the appended claims, it is tobe understood that the invention can be practiced otherwise than asspecifically described.

We claim:
 1. A stable aqueous pigment paste comprising:A. 2 to 50percent by weight based on weight of (B) of a water-dispersible cationicpolymer produced by reacting a 1,2-epoxy group-containing material witha material selected from the group consisting of amine salts,phosphine-acid mixtures and sulfide-acid mixtures, said cationic polymerhaving a ratio of final quaternary onium salt groups to initial epoxidegroups greater than about 0.4 to 1; and B. a pigment dispersed therein.2. The pigment paste of claim 1 wherein the onium salt is an ammoniumsalt.
 3. The pigment paste of claim 1, wherein the ratio of final oniumsalt groups to initial epoxide groups is greater than about 0.6 to
 1. 4.The pigment paste of claim 1, wherein said polymer contains oxyalkylenegroups in the molecule.
 5. The pigment paste of claim 1, wherein atleast a portion of said onium salt is a salt of an acid having adissociation constant greater than 1 × 10⁻ ⁵.
 6. The pigment of claim 1,wherein said 1,2-epoxy group-containing material is a polyglycidyl etherof a polyphenol.